Evaporation flash evaporation crystallization equipment

Abstract

The utility model discloses evaporation flash evaporation crystallization equipment, which is cylindrical closed equipment consisting of a cylindrical evaporator, a flash evaporation chamber, an upper crystallizer structure, a middle crystallizer structure and a lower crystallizer structure, has the functions of evaporation, flash evaporation and crystallization, can be used for evaporation, flash evaporation and crystallization of solutions, and can be widely applied to the flow of industrial production. Detachable connecting piece flanges are arranged at the raw material inlet A, the steam inlet C, the condensed water outlet D, the gas phase outlet F, the exhaust inlet G, the target product outlet J, the exhaust outlet L and the circulating material outlet M and are detachably connected with the whole production system. The device is reasonable in layout, simple in structure, small in fluid resistance, uniform in fluid distribution, easy to install, overhaul, maintain and clean, wide in application range and suitable for evaporation, flash evaporation and crystallization production systems of various specifications and models.

Description

Technical Field

[0001] The utility model relates to the technical field of evaporation, concentration and crystallization of solutions, in particular to evaporation flash crystallization equipment. Background Art

[0002] In industrial production, heating evaporation and flash concentration of solutions are often used. To achieve this purpose, independently set evaporators and flash chambers are usually used. Through the evaporator and flash chamber, a large amount of volatile components will be converted into gas and evaporated out of the flash chamber. The solution will be concentrated and cooled to achieve the purpose of separating different components. The solution from the system that needs to be heated for evaporation and flash concentration is first heated by an independently set evaporator. After heating and heating, the hot solution is sent to an independently set flash chamber. The gas flashed out in the flash chamber is discharged from the top outlet of the flash chamber, and the concentrated and cooled solution is discharged from the bottom outlet of the flash chamber. The solution out of the flash chamber can be used as the target product to go to the system. After evaporation and flash evaporation, if the target product crystallizes, a part of the target product can be mixed with the raw materials from the system as a circulating solution and returned to the evaporator. While controlling the circulation ratio, preventing fluid boiling in the evaporator heating tubes, reducing the temperature difference between the evaporator inlet and outlet, and careful operation can alleviate the problem of crystallization clogging equipment and pipes to a certain extent, salt deposits and scaling will eventually form on the evaporator's inner walls and in the pipes connecting the equipment. This not only hinders heat transfer but also requires cleaning after a period of operation. Separately locating the evaporator and flash chamber not only increases the height and span of the plant, but also increases the length of the connecting pipes and the resistance loss along the way, making inspection, maintenance, and component replacement more difficult. Utility Model Content

[0003] The purpose of the utility model is to effectively combine an evaporator, a flash chamber and a crystallizer to form a multifunctional device, to make up for the shortcomings of a single evaporator and a flash chamber, and to provide an evaporation flash crystallization device that integrates evaporation, flash evaporation and crystallization. The evaporation flash crystallization device has uniform internal fluid distribution, a reasonable overall structural layout, a simple structure, low fluid resistance, easy installation and repair, easy maintenance and cleaning, and is suitable for evaporation, flash evaporation and crystallization production systems of various specifications and models.

[0004] The purpose of the utility model can be achieved through the following technical solutions:

[0005] An evaporation flash crystallization device comprises an evaporator, a flash chamber and a crystallizer from top to bottom; a raw material inlet A is provided at the top of the evaporator, a steam inlet C and a condensed water outlet D are provided on the side shell side; a gas phase outlet F and an exhaust inlet G are respectively provided on both sides of the flash chamber, a flash cooling liquid outlet cone is installed at the bottom of the flash chamber, and a material outlet H is provided at the bottom of the flash cooling liquid outlet cone; an exhaust outlet L, a circulating material outlet M and a target product outlet J are respectively provided on both sides of the crystallizer from top to bottom, and an atmospheric leg is installed in the crystallizer, and the atmospheric leg is located on the longitudinal axis of the crystallizer.

[0006] As a preferred embodiment of the present invention, a vortex-breaking cross baffle is installed in the flash cooling liquid outlet cone, and the vortex-breaking cross baffle is located on the longitudinal axis of the flash chamber.

[0007] As a preferred embodiment of the present invention, the exhaust inlet G is connected to the exhaust outlet L through an exhaust pipe.

[0008] As a preferred embodiment of the present invention, the raw material inlet A is located on the longitudinal axis of the evaporator, and the raw material inlet A is connected to the circulating material outlet M through a circulating material pipeline.

[0009] As a preferred embodiment of the present invention, the exhaust outlet L and the exhaust inlet G are located on the same side.

[0010] As a preferred embodiment of the present invention, the steam inlet C is higher than the condensed water outlet D.

[0011] As a preferred embodiment of the present invention, the atmospheric leg is placed vertically, the top of the atmospheric leg is fixedly connected to the material outlet H, and the bottom outlet K is trumpet-shaped; the bottom outlet K of the atmospheric leg is lower than the height of the target product outlet J.

[0012] As a preferred embodiment of the present invention, the raw material inlet A, steam inlet C, condensate outlet D, gas phase outlet F, exhaust inlet G, target product outlet J, exhaust outlet L and circulating material outlet M are all provided with detachable connectors; more preferably, the detachable connectors are flanges.

[0013] As a preferred embodiment of the present invention, the evaporator is a cylindrical falling film evaporator, and the evaporator and / or the flash chamber and the crystallizer are vertically installed.

[0014] Beneficial effects of the utility model:

[0015] After passing through the evaporator, the solution enters the flash chamber, where it is vacuum-evaporated and supersaturated. A crystallizer is added below the flash chamber. The hot solution evaporates within the flash chamber, lowering the temperature and causing the solution to become slightly supersaturated but still within the metastable zone. Therefore, a large number of crystal nuclei are not generated. As the supersaturated solution flows from the atmospheric leg down into the crystallizer below the flash chamber, the supersaturation is relieved on the surface of the crystals suspended therein, allowing the existing crystals to grow. This method reduces and delays crystallization and scaling on the inner walls of the heating tubes, increasing the evaporator cleaning cycle from one week to three to six weeks, thereby increasing the production unit's operating rate.

[0016] The purpose of this utility model is to effectively combine an evaporator, a flash chamber, and a crystallizer to form a multifunctional integrated device, thereby overcoming the shortcomings of a single evaporator and flash chamber. The device provides an evaporation-flash crystallization device that integrates evaporation, flash evaporation, and crystallization. The device has uniform internal fluid distribution, a rational overall structural layout, a simple structure, low fluid resistance, and is easy to install, repair, maintain, and clean. It can mix raw materials with circulating materials, indirectly exchange heat between materials and saturated steam, evaporate and concentrate heated materials under negative pressure, and crystallize and discharge concentrated materials. The device is suitable for evaporation, flash evaporation, and crystallization production systems of various specifications and models. The use of this device not only reduces the height and span of the factory building, but also reduces the length of the connecting pipelines and the resistance loss along the way. The device can be used to concentrate dilute phosphoric acid, produce superphosphoric acid, and evaporate, concentrate, and crystallize various solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front view of the utility model.

[0018] Figure 2 It is a schematic diagram of the AA section of the present invention.

[0019] Among them, there are evaporator-1, flash chamber-2, crystallizer-3, flash cooling liquid outlet cone-4, vortex breaking cross baffle-5, atmospheric leg-6, exhaust pipe-7. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the drawings, where the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 、 2 As shown, an evaporation flash crystallization equipment is shown, which includes an evaporator 1, a flash chamber 2 and a crystallizer 3 from top to bottom; a raw material inlet A is provided at the top of the evaporator 1, and the raw material inlet A is located on the longitudinal axis of the evaporator 1, and a steam inlet C and a condensed water outlet D are provided on the side shell of the evaporator 1; a gas phase outlet F and an exhaust inlet G are respectively provided on both sides of the flash chamber 2, and the gas phase outlet F is connected to the vacuum system, a flash liquid outlet cone 4 is installed at the bottom of the flash chamber 2, and a material outlet H is provided at the bottom of the flash liquid outlet cone 4, and a vortex-breaking cross baffle 5 is installed in the flash liquid outlet cone 4, and the vortex-breaking cross baffle 5 is located on the longitudinal axis of the flash chamber 2; an atmospheric leg 6 is installed in the crystallizer 3, and the atmospheric leg 6 is located on the longitudinal axis of the crystallizer 3, and an exhaust outlet L, a circulating material outlet M and a target product outlet J are respectively provided on both sides of the crystallizer 3 from top to bottom, the exhaust outlet L is connected to the exhaust inlet G through an exhaust pipe 7, and the circulating material outlet M is connected to the raw material inlet A through a circulating material pipeline.

[0023] The exhaust outlet L and the exhaust inlet G are located on the same side; the steam inlet C is higher than the condensed water outlet D.

[0024] The atmospheric leg 6 is placed vertically, with its top fixedly connected to the material outlet H and the bottom outlet K being trumpet-shaped; the bottom outlet K of the atmospheric leg 6 is lower than the height of the target product outlet J.

[0025] The raw material inlet A, steam inlet C, condensate outlet D, gas phase outlet F, exhaust inlet G, target product outlet J, exhaust outlet L and circulating material outlet M are all provided with detachable connectors; the detachable connectors are flanges.

[0026] The evaporator 1 is a cylindrical falling film evaporator, and the evaporator 1, the flash chamber 2 and the crystallizer 3 are vertically installed.

[0027] The gas phase outlet F and the exhaust inlet G are both located above the liquid level of the flash chamber 2 , and the exhaust outlet L is located above the liquid level of the crystallizer 3 .

[0028] The production method using the above equipment includes the following steps. There are many materials that can be selected. The wet-process dilute phosphoric acid concentration is taken as an example:

[0029] (1) Feeding and evaporation: Saturated steam (temperature 133°C, pressure 301 kPa) from the boundary zone enters the shell side of evaporator 1 from the upper steam inlet C of evaporator 1 on the upper part of the evaporation flash crystallization equipment, and exchanges heat with the phosphoric acid in the tube side; the saturated steam is cooled into condensed water and discharged to the system from the lower condensed water outlet D of evaporator 1.

[0030] Circulating phosphoric acid (containing a P2O5 mass concentration of 48% and a temperature of 76°C) from the circulating material outlet M in the middle of the lower crystallizer of the evaporation flash crystallization equipment is mixed with dilute phosphoric acid (containing a P2O5 mass concentration of 28.6% and a temperature of room temperature) as a raw material from the system. The mixed phosphoric acid then enters evaporator 1 through phosphoric acid inlet A at the top of evaporator 1 and enters the tube side of evaporator 1 through tube side inlet B of evaporator 1. The phosphoric acid flows down along the inner wall of the tube and exchanges heat with saturated steam in the shell side. The phosphoric acid in the tube side is heated (temperature of 78.5°C) and then flows into flash chamber 2 below evaporator 1 through connection E between evaporator 1 and flash chamber 2.

[0031] (2) Flash evaporation and dehydration: The hot phosphoric acid from the evaporator 1 at the upper part of the evaporation flash crystallization equipment is flashed in the flash chamber 2. When the gas phase pressure (10 kPa) is lower than the atmospheric pressure, a portion of the water is removed, and the concentration of the hot phosphoric acid increases (containing a P2O5 mass concentration of 48%), while the temperature decreases (temperature 76°C). The hot phosphoric acid flows from the material outlet H of the flash chamber 2 into the crystallizer 3 below the flash chamber 2; the vacuum gas coming out of the gas phase outlet F at the upper part of the flash chamber 2 is discharged to the system.

[0032] (3) Crystallization and discharging: Concentrated phosphoric acid (containing 48% P2O5 by mass and 76°C) from the flash chamber 2 in the middle of the evaporation flash crystallization equipment enters the crystallizer 3 from the bottom outlet K. The residence time of the concentrated phosphoric acid in the crystallizer 3 is twice that of the crystallizer 3 without the crystallizer 3. The concentrated phosphoric acid begins to crystallize and gradually grows (solid content 4%). The grown crystals sink to the bottom of the crystallizer 3 and are discharged from the target product outlet J at the bottom of the crystallizer 3 together with the target product. The remaining concentrated phosphoric acid is discharged from the crystallizer 3 from the circulating phosphoric acid outlet M in the middle of the crystallizer 3 as circulating phosphoric acid. After mixing with the raw material from the system, dilute phosphoric acid, it enters the evaporator 1 from the raw material inlet A at the top of the evaporator 1. The mass ratio of circulating phosphoric acid to the target product, concentrated phosphoric acid, is 180:1.

[0033] The results of the operation of the present invention are shown in Table 1.

[0034] Table 1 Performance evaluation results of 60 tons / day concentrated phosphoric acid unit

[0035]

Claims

1. An evaporation flash crystallization device, characterized in that: The evaporation flash crystallization equipment comprises an evaporator (1), a flash chamber (2) and a crystallizer (3) from top to bottom; a raw material inlet A is provided at the top of the evaporator (1), and a steam inlet C and a condensed water outlet D are provided on the side shell side; a gas phase outlet F and an exhaust inlet G are provided on both sides of the flash chamber (2), a flash cooling liquid outlet cone (4) is installed at the bottom of the flash cooling liquid outlet cone (4), and a material outlet H is provided at the bottom of the flash cooling liquid outlet cone (4); an exhaust outlet L, a circulating material outlet M and a target product outlet J are provided on both sides of the crystallizer (3) from top to bottom, and an atmospheric leg (6) is installed in the crystallizer (3), and the atmospheric leg (6) is located on the longitudinal axis of the crystallizer (3).

2. The evaporation flash crystallization equipment according to claim 1, characterized in that: A vortex-breaking cross baffle (5) is installed in the flash cooling liquid outlet cone (4), and the vortex-breaking cross baffle (5) is located on the longitudinal axis of the flash chamber (2).

3. The evaporation flash crystallization equipment according to claim 1, characterized in that: The exhaust inlet G is connected to the exhaust outlet L through an exhaust pipe (7).

4. The evaporation flash crystallization equipment according to claim 1, characterized in that: The raw material inlet A is located on the longitudinal axis of the evaporator (1), and the raw material inlet A is connected to the circulating material outlet M via a circulating material pipeline.

5. The evaporation flash crystallization equipment according to claim 1, characterized in that: The exhaust outlet L and the exhaust inlet G are located on the same side.

6. The evaporation flash crystallization equipment according to claim 1, characterized in that: The steam inlet C is higher than the condensed water outlet D.

7. The evaporation flash crystallization equipment according to claim 1, characterized in that: The atmospheric leg (6) is placed vertically, with its top fixedly connected to the material outlet H, and its bottom outlet K is trumpet-shaped; the bottom outlet K of the atmospheric leg (6) is lower than the height of the target product outlet J.

8. The evaporation flash crystallization equipment according to any one of claims 1 to 7, characterized in that: The raw material inlet A, steam inlet C, condensed water outlet D, gas phase outlet F, exhaust inlet G, target product outlet J, exhaust outlet L and circulating material outlet M are all provided with detachable connectors.

9. The evaporation flash crystallization equipment according to any one of claims 1 to 7, characterized in that: The evaporator (1) is a cylindrical falling film evaporator, and the evaporator (1) and / or the flash chamber (2) and the crystallizer (3) are vertically installed.

10. The evaporation flash crystallization equipment according to claim 8, characterized in that: The detachable connecting piece is a flange.

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